Conventionally, there has been proposed a three-dimensional object detection device which detects horizontal edges or vertical edges in an actual space from a bird's eye view obtained by subjecting a captured image to viewpoint conversion to the bird's eye point of view, and then detects a three-dimensional object such as a vehicle by using the number of these edges. In this three-dimensional object detection device, the vertical edges in the actual space get projected and appear on the bird's eye view as a group of radial straight lines passing a viewpoint of a camera. On the basis of this knowledge, the three-dimensional object detection device detects the three-dimensional object by detecting the vertical edges and then using the amount of the vertical edges (see Patent Document 1).